Various surgical procedures are routinely carried out intravascularly or intraluminally. For example, in the treatment of vascular disease, such as arteriosclerosis, it is a common practice to access the artery and insert an instrument (e.g., a balloon or other type of catheter) to carry out a procedure within the artery. Such procedures usually involve the percutaneous puncture of the artery so that an introducer (also referred to as an introducer sheath and an insertion sheath) may be placed in the artery and thereafter instruments (e.g., catheters) may pass through the introducer to an operative position within the artery.
The introducer is typically designed to penetrate the skin and wall of the blood vessel and be positioned within the blood vessel so that surgical implements and medical devices may be advanced and withdrawn through the introducer. In this way, even when multiple surgical implements and medical devices are used in a single procedure, there is a single placement of the introducer through the skin and vessel wall.
Introducers typically include valves that prevent back flow of blood through the introducer while permitting advancement of the surgical implements and medical devices to the vessel. Introducer valves are typically categorized as passive or active. A passive valve generally relies on the deformation of a resilient sealing member by the implement or medical device that is inserted through the valve to form the desired fluid-tight seal. An active valve typically includes a mechanism that moves a sealing member into contact with the implement or medical device.
Whether active or passive, valves generally suffer from a common disadvantage of failing to provide an effective hemostatic seal with a wide range of sizes of implements and medical devices that are advanced through the valve. Passive valves tend to impose substantial friction forces on at least some types of implements and medical devices (e.g., larger devices), thereby making it difficult for the user to insert and withdraw the implement or medical device relative to the introducer. Moving parts in an active valve have greater potential for failure.
The complexity of common endovascular surgical procedures has placed heightened demands on the ability of the introducer to provide a seal with a variety of implements and medical devices. It is common to have a range in size for such implements and medical devices from various small guidewires (0.01 inch diameter) to relatively large dilators and other implements (e.g., 5 French (F) to 20 F).
Opportunities exist for improving such sealing members, especially in large bore introducers (e.g., 18 F) through which different sized and shaped devices are delivered into a patient.